Electron‐transfer (redox) thermochromism was successfully used for switching the conductance of semiconductors, by introducing a thermally active organic component into an inorganic semiconducting ...framework. A moisture‐resistant semiconductor {(MV)2Pb7Br18}n (MV2+=methyl viologen cation) has been prepared through an in situ synthetic method for MV2+. It features a rare 3D haloplumbate open framework and unprecedented electron‐transfer thermochromic behavior in haloplumbates. The electrical conductivity of this compound dropped significantly after coloration and restored after decoloration, which was satisfactorily explained by valence band XPS and theoretical data. This work not only offers a new approach to modify electrical properties of semiconductors without altering components or structures, but may lead to the development of over‐temperature color indicators, circuit overload protectors or photovoltaic materials.
Conductance switch: Electron‐transfer (redox) thermochromism was successfully used for switching the conductance of semiconductors (see picture). The application may lead to the development of over‐temperature color indicators or circuit overload protectors.
•The SWR was much quicker than the SWI under a small horizontal hydraulic gradient.•Hysteresis was found in the relationship between the saltwater wedge toe location and salt mass.•The response of ...SWI and SWR to the inland watertable variations was affected by tidal conditions.
Based on combined laboratory experiments and numerical simulations, this paper examined seawater intrusion (SWI) and seawater retreat (SWR) processes caused by abrupt inland watertable changes in a laboratory-scale unconfined aquifer (length of 7.7 m and thickness of 1.0 m) subjected to a synthetic sinusoidal tide. The results showed that the salinity distribution was relatively stable and that SWI and SWR processes were almost temporally symmetrical given relatively large horizontal hydraulic gradients (0.0269, 0.0209 and 0.0149) between the inland watertable and the mean sea level. However, the salt distribution changed significantly in response to the inland watertable variations when the horizontal hydraulic gradient was relatively small (0.0030). The speed of the SWI and SWR response to the inland watertable variations was temporally asymmetric, e.g., SWR was quicker than SWI by a factor of 9 with respect to the observed saltwater wedge toe locations. As a relatively thick mixing zone (transition between freshwater and saltwater zones) was induced by the tide, simulated saltwater wedge toe locations, as indicated by the 5%, 50% and 95% isohalines, changed inconsistently. Different hysteresis behaviors were found in the relationship between the SW toe locations and total salt mass stored in the aquifer. Sensitivity analyses demonstrated that the response of both SWI and SWR to the inland watertable variations could be prolonged by a decreased tidal amplitude or decreased tidal period.
•Evaporation increases pore-water salinity in the shallow soil layer.•Salt is trapped in the shallow soil layer by evaporation.•A higher mean sea level enhances the evaporation-induced salt trapping.
...Ocean surge inundation occurs frequently in low-lying coastal areas worldwide. While studies have been conducted to examine aquifer salinization and recovery caused by ocean surge inundation, evaporation is predominantly overlooked. Based on numerical simulations considering variably saturated, density-dependent pore-water flow and salt transport, this study examines the combined effects of evaporation and ocean surge inundation on soil salinization in coastal unconfined aquifers. The results show that evaporation enhances soil salinization caused by ocean surge inundation. Due to evaporation-induced water uptake, the downward movement of salt is weakened and the salt from the ocean surge inundation is significantly trapped in the unsaturated zone. The pore-water salinity in the shallow soil layer is increased by soil evaporation, particularly in the low-elevation area with longer seawater inundation. The sensitive analysis shows that the evaporation-enhanced soil salinization is more remarkable for silt-loam and clay-loam aquifers rather than sandy-loam aquifers. A higher mean sea level favors salt trapping in the shallow soil layer of aquifers. These results demonstrate the importance of evaporation on soil salinization caused by ocean surge inundation, and that could be considered in future studies.
Tides and seasonally varying inland freshwater input, with different fluctuation periods, are important factors affecting flow and salt transport in coastal unconfined aquifers. These processes ...affect submarine groundwater discharge (SGD) and associated chemical transport to the sea. While the individual effects of these forcings have previously been studied, here we conducted physical experiments and numerical simulations to evaluate the interactions between varying inland freshwater input and tidal oscillations. Varying inland freshwater input was shown to induce significant water exchange across the aquifer‐sea interface as the saltwater wedge shifted landward and seaward over the fluctuation cycle. Tidal oscillations led to seawater circulations through the intertidal zone that also enhanced the density‐driven circulation, resulting in a significant increase in the total SGD. The combination of the tide and varying inland freshwater input, however, decreased the SGD components driven by the separate forcings (e.g., tides and density). Tides restricted the landward and seaward movement of the saltwater wedge in response to the varying inland freshwater input in addition to reducing the time delay between the varying freshwater input signal and landward‐seaward movement in the saltwater wedge interface. This study revealed the nonlinear interaction between tidal fluctuations and varying inland freshwater input will help to improve our understanding of SGD, seawater intrusion, and chemical transport in coastal unconfined aquifers.
Key Points
The lower and upper part of the saltwater‐freshwater interface are, respectively, affected by varying inland freshwater input and tides
Interaction between tidal fluctuations and varying inland freshwater input is nonlinear
Tide reduces the time lags in the response of the saltwater wedge and submarine groundwater discharge to the varying inland freshwater input
•Driving forces on flow and transport, and chemical behavior in subterranean estuaries reviewed.•Need for better understanding of interactions between physical and biogeochemical processes.•Need to ...consider influence of real work complexities such aquifer heterogeneities.
Sustainable coastal resource management requires sound understanding of interactions between coastal unconfined aquifers and the ocean as these interactions influence the flux of chemicals to the coastal ocean and the availability of fresh groundwater resources. The importance of submarine groundwater discharge in delivering chemical fluxes to the coastal ocean and the critical role of the subterranean estuary (STE) in regulating these fluxes is well recognized. STEs are complex and dynamic systems exposed to various physical, hydrological, geological, and chemical conditions that act on disparate spatial and temporal scales. This paper provides a review of the effect of factors that influence flow and salt transport in STEs, evaluates current understanding on the interactions between these influences, and synthesizes understanding of drivers of nutrient, carbon, greenhouse gas, metal and organic contaminant fluxes to the ocean. Based on this review, key research needs are identified. While the effects of density and tides are well understood, episodic and longer-period forces as well as the interactions between multiple influences remain poorly understood. Many studies continue to focus on idealized nearshore aquifer systems and future work needs to consider real world complexities such as geological heterogeneities, and non-uniform and evolving alongshore and cross-shore morphology. There is also a significant need for multidisciplinary research to unravel the interactions between physical and biogeochemical processes in STEs, as most existing studies treat these processes in isolation. Better understanding of this complex and dynamic system can improve sustainable management of coastal water resources under the influence of anthropogenic pressures and climate change.
Cutaneous wound healing and regeneration have become a recognized health challenge in the world, which causes severe damage to the mental and physical health of patients. Human adipose-derived ...mesenchymal stem cells (hADSC) play an essential role in wound healing via their paracrine function. Exosomes secreted by hADSC may contribute to this progress. In this study, we investigated the potential clinical application roles of hADSC and hADSC-derived exosomes (hADSC-Exo) in cutaneous wound healing.
hADSC-Exo was isolated from human hADSC by ultracentrifugation. Mice were subjected to a full-thickness skin biopsy experiment and treated with either control vehicle or hADSC or hADSC-Exo by smearing administration (sm) or subcutaneous administration (sc) or intravenous administration (iv). The efficacy of hADSC and hADSC-Exo on wound healing was evaluated by measuring wound closure rates, histological analysis.
Combined application of local hADSC-Exo smearing and hADSC/hADSC-Exo intravenous administration offered the additional benefit of promoting wound healing, accelerating re-epithelialization, reducing scar widths, and enhancing angiogenesis and collagen synthesis. Either topical application of hADSC-Exo or systemic administration with hADSC/hADSC-Exo appeared more effective in stimulating cell proliferation, inhibiting cell apoptosis and inflammation, and promoting skin elasticity and barrier integrity, with increased genes expression of PCNA, VEGF, collagen III, Filaggrin, Loricrin, and AQP3, with decreased genes expression of TNF-alpha.
Our findings suggest that the combined administration of hADSC/hADSC-Exo can facilitate cutaneous wound healing and reduce scar formation. These data provide the first evidence for the feasibility of smearing of hADSC-Exo as a cell-free therapy in treating cutaneous wounds, and the potential clinical value of combined administration of hADSC/hADSC-Exo.
Macropores such as crab burrows are a common feature of salt marsh sediment and are recognized as an important factor influencing pore‐water flow in salt marshes. In this study, we examined the ...effect of macropores on saline water evaporation and pore‐water salinity based on laboratory experiments and numerical simulations. Soil columns with and without an artificial macropore were packed with clay‐loam and were set with different hydraulic heads fixed at the bottom. The results showed that increase in pore‐water salinity significantly reduced evaporation rates. The preferential flow induced by macropores recharged the soil surrounding macropores and maintained higher evaporation rates in comparison with homogeneous soil without macropores. As macropores induced lateral flow, the pore‐water salinity in shallow soil around the macropores was reduced but that in the area away from the macropores was increased. These impacts were more remarkable on the soil layers with higher hydraulic heads. A sensitivity analysis showed that with a higher initial pore‐water salinity, the macropore's impact on soil evaporation rates was more remarkable for both clay‐loam and silt‐loam. These results revealed the effect of macropores on soil evaporation processes and soil conditions, and also shed light on associated biogeochemical processes in salt marshes.
Key Points
Macropores increased evaporation from marsh soil with high hydraulic heads
Macropores altered pore‐water flow and salinity distributions
Macropores' impacts were more remarkable on soil with high hydraulic heads
Salt is a key solute in salt marshes and under the influence of evapotranspiration can accumulate to a high concentration level in the marsh soil and precipitate in the solid form to become a ...significant stressor for plants, affecting marsh plant productivity and ecological zonation. Numerical simulations of coupled pore water flow and salt transport were conducted to examine how spring‐neap tides and evaporation combine to influence salt dynamics and distribution patterns in marshes. The salt pan formation was simulated with a sandy loam marsh soil subjected to a medium rate of potential evaporation. The critical condition for the salt pan formation was underpinned by hydraulic connection between the marsh surface and water table to sustain evaporation in the supratidal zone. Both low soil permeability and overly high potential evaporation were found to break the hydraulic connection. In this case, the surface soil salinity increased gradually over the intertidal zone to a maximum around the spring high tide mark followed by a rapid decrease to a lower constant level across the supratidal zone. This salinity distribution pattern has also been observed in the field. In both salt marshes with and without salt pans, excessive salt accumulated on the marsh surface due to evaporation was removed by tidally induced circulating flow and/or flow driven by density gradients associated with the accumulated salt. The salt dynamics and distribution patterns revealed here, especially the salt pan formation simulated for the first time, have important implications for studies of marsh plant growth and overall eco‐functions.
Key Points
Salt pan formation is simulated under the combined influence of spring‐neap tides and evaporation
Salt pans are more likely to form in sandy soil marshes subjected to a moderate rate of potential evaporation
Salinity gradients due to evaporation modify tide‐driven circulation in the intertidal zone and drive pore water flow in the supratidal zone
To report tumor local progression-free outcomes after treatment with single-dose, image-guided, intensity-modulated radiotherapy and hypofractionated regimens for extracranial metastases from renal ...cell primary tumors.
Between 2004 and 2010, 105 lesions from renal cell carcinoma were treated with either single-dose, image-guided, intensity-modulated radiotherapy to a prescription dose of 18-24 Gy (median, 24) or hypofractionation (three or five fractions) with a prescription dose of 20-30 Gy. The median follow-up was 12 months (range, 1-48).
The overall 3-year actuarial local progression-free survival for all lesions was 44%. The 3-year local progression-free survival for those who received a high single-dose (24 Gy; n = 45), a low single-dose (<24 Gy; n = 14), or hypofractionation regimens (n = 46) was 88%, 21%, and 17%, respectively (high single dose vs. low single dose, p = .001; high single dose vs. hypofractionation, p < .001). Multivariate analysis revealed the following variables were significant predictors of improved local progression-free survival: 24 Gy dose compared with a lower dose (p = .009) and a single dose vs. hypofractionation (p = .008).
High single-dose, image-guided, intensity-modulated radiotherapy is a noninvasive procedure resulting in high probability of local tumor control for metastatic renal cell cancer generally considered radioresistant according to the classic radiobiologic ranking.
Soil salinity is an increasingly serious problem worldwide that reduces agricultural output potential. Selected beneficial soil bacteria can promote plant growth and augment tolerance to biotic and ...abiotic stresses. Bacillus subtilis strain GB03 has been shown to confer growth promotion and abiotic stress tolerance in the model plant Arabidopsis thaliana. Here we examined the effect of this beneficial soil bacterium on salt tolerance in the legume forage crop, white clover. Plants of white clover (Trifolium repens L. cultivar Huia) were grown from seeds with or without soil inoculation of the beneficial soil bacterium Bacillus subtilis GB03 supplemented with 0, 50, 100, or 150 mM NaCl water into soil. Growth parameters, chlorophyll content, malondialdehyde (MDA) content and osmotic potential were monitored during the growth cycle. Endogenous Na(+) and K(+) contents were determined at the time of harvest. White clover plants grown in GB03-inoculated soil were significantly larger than non-inoculated controls with respect to shoot height, root length, plant biomass, leaf area and chlorophyll content; leaf MDA content under saline condition and leaf osmotic potential under severe salinity condition (150 mM NaCl) were significantly decreased. Furthermore, GB03 significantly decreased shoot and root Na(+) accumulation and thereby improved K(+)/Na(+) ratio when GB03-inoculated plants were grown under elevated salt conditions. The results indicate that soil inoculation with GB03 promotes white clover growth under both non-saline and saline conditions by directly or indirectly regulating plant chlorophyll content, leaf osmotic potential, cell membrane integrity and ion accumulation.
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